Solve for $p$ : $25 = 7 + p$
Solution: Subtract $7$ from both sides: $ \begin{eqnarray} \\ \hphantom{25 {- 7}} &\hphantom{=}& \hphantom{p} \\ 25 &=& 7 + p \\ \\ {-7} && {-7} \\ \end{eqnarray} $ $ \begin{eqnarray} \\ 25 {- 7} &=& p \\ \end{eqnarray} $ Simplify. $ p = 18$